Like Republicans often do, presidential nominee Donald Trump has repeatedly promised to cut taxes, particularly on the middle class.

"We're cutting taxes for the middle class and I will tell you we are cutting them big league," he said during a recent town hall in St. Louis, according to CNBC.

But a pair of recent papers cast serious doubts on that claim, and suggest that some of Trump's tax proposals would — in fact — effectively raise taxes on millions of middle- and low-income families, particularly those led by single parents.

Trump's plan "would cause many large families and single parents to face tax increases," since they would no longer qualify for certain deductions — which reduce taxable income — and might find themselves in a higher tax bracket, according to the latest analysis from the left-leaning Tax Policy Center released Tuesday.

Roberton Williams, a fellow at the Urban-Brookings Tax Policy Center, said in a phone interview that while some of those families would see savings from other provisions in Trump's child care plan, not all affected families would.

"If you're a single parent with kids, your taxable income is going to go up and your bracket is going to go up," Williams said.

Indeed, if you want to talk about "big league" numbers, try 7.8 million: That's how many low- and middle-income families who see their taxes go up under Trump's plan, according to a paper by Lily Batchelder, a law professor at New York University and a former deputy director of the National Economic Council.

Trump "does provide a small refundable credit for child care, which benefits lower-income families," Batchelder said in an email to Mic. "However, it does not nearly compensate for the three ways in which he raises taxes on single families: repealing personal exemptions, repealing the head-of-household filing status, and raising the 10% bracket to 12%."

Under Batchelder's analysis, a single parent with three kids making $50,000 a year and spending a little less than $6,000 a year in child care costs would pay an additional $1,188 in annual taxes.

Even some of the families highlighted on Trump's campaign site would see a tax hike, assuming Batchelder's analysis plays out.

"The Trump campaign website states that a married couple with $50,000 in earnings, two children, and $8,000 in child care costs would see their tax bill cut by 35%," Batchelder wrote. "In reality, that family would receive a tax cut of only $93, or 0.2% of their after-tax income. And if the family had three children, that tax cut would become a tax increase of nearly $450."

Trump's tax increases on single-parent-led families are likely in part a consequence of criticism of earlier drafts of Trump's plan, which experts on both sides of the aisle panned as being too costly.

"He was looking for ways to reduce the revenue loss," Williams said. "The changes that he's made since the original plan have reduced the cost by about a third."

Some of the people who would be affected by Trump's tax hikes could very well be current Trump supporters.

According to a May Gallup poll, Democratic presidential nominee Hillary Clinton is more popular among married couples with children under 18 — who could see tax hikes under Trump, particularly if they have lots of children. But at only three percentage points, Clinton's lead is narrow.

White voters without college degrees tend to favor Trump, according to a poll analysis from theNew York Times, and a study published by Brookings suggests that less-educated Americans are more likely to be single parents — a growing demographic across all races.

To be fair, single moms tend to vote overwhelmingly Democratic.

But roughly a quarter of them didn't vote for Obama in the last two presidential elections, according to an analysis of exit polls by the Washington Post. That's millions of votes arguably up for grabs.

Then again, former Republican nominee Mitt Romney was never caught bragging about grabbing women "by the pussy."

The Trump campaign did not immediately respond to a request for comment.